[Javascript] AJAX app causing excessive browser memory usage

[Matt Warden]

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Rick Emery wrote:
> var xmlList = xhr.responseXML;

Where is the code which handles the AJAX request? That's the most likely
place for a memory leak. And then let us see the code that handles
readystate change, too.

>       tdPriority = null;
...
>       tdType = null;
...
>       trow = null;

These aren't helping you at all, so don't bother. The equivalent happens
when the variables fall out of scope.

>    tmpBody = document.getElementById("eltable").replaceChild(tbody,
> oldBody);

If you don't need the result of the right hand side, then don't assign
it to a variable.

> xmlList = null;

Keep this one.

> In both Internet Explorer and Firefox, I can see that, each time the 
> xhr response is received and the data updated, the memory consumption 
> of the browser  process increases. I expect this if the new table body 
> has more rows than the old table, but it happens even when there are 
> fewer rows. If I let it run over the weekend, it will eventually 
> consume all of the available memory of the machine. Closing the  browser
> is the only way to free the memory.

Well you're creating a new XHR object every 30 seconds. Not a problem if
you're handling its destruction properly, but I have a hunch you are not.

But we need to see that code.

In the meantime, do yourself a favor and download Drip:
http://outofhanwell.com/ieleak/index.php?title=Main_Page

- --
Matt Warden
Oxford, OH, USA
http://mattwarden.com


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